Electric garage door opener

ABSTRACT

A mechanism for operating a door including a reversible electric motor composed of a rotatable armature and a rotatable rotor connected therewith to a rotatable shaft having a rotatable speed, a worm locked on said shaft in working engagement with said shaft, a worm gear in working engagement with said worm having a given rotational speed proportioned to the rotational speed of the worm, door closure actuating means operatively connected with the worm gear, limit switch means electrically connected to the motor and disposed in a region adjacent to one of the screw holding end covers of the motor together said screw contacting the limit switch means when the rotational speed of said worm gear varies from the rotational speed of said rotor causing said armature and its screws to rotate in the opposite direction.

United States Patent 91 Lafontaine Jan. 22, 1974 1 ELECTRIC GARAGE DOOR OPENER [76]. inventor: Lucien Latontaine, 637 Place Fleury, Montreal, Quebec, Canada 221 Filed: Jan. 29, 1973 21 App1.No.:327,642

Primary ExaminerB. Dobeck 5 7 ABSTRACT A mechanism for operating a door including a reversible electric motor composed of a rotatable armature and a rotatable rotor connected therewith to a rotatable shaft having a rotatable speed, a worm locked on said shaft in working engagement with said shaft, a worm gear in working engagement with said worm having a given rotational speed proportioned to the rotational speed of the worm, door closure actuating means operatively connected with the worm gear, limit switch means electrically connected to the motor and disposed in a region adjacent to one of the screw holding end covers of the motor together said screw contacting the limit switch means when the rotational speed of said worm gear varies from the rotational speed of said rotor causing said armature and its screws to rotate in the opposite direction.

2 Claims, 3 Drawing Figures PATENIEDJANZZIGN ROTATION ELECTRIC GARAGE DOOR OPENER The present invention relates to a mechanism to actuate limit switches for stopping an electric motor or reversing its polarity in Garage door operators.

The most important requirement of the garage door operator is that it be absolutely safe in its operation and incapable of injuring any person using it or in the vicinity of the door as it is opened or closed or of damaging any property that might be in the way of the door as it is automatically opened or closed.

The mechanism of the invention includes a positive means for immediately arresting the opening or closing motion of the door or reversing said motion should the door encounters an obstacle in its way down or up.

Another object is its high degree of reliability, its simplicity and the cheapness in construction.

Further details of the invention will become apparent from the accompanying single sheet of drawing and from the following description and claim.

FIG. 1 represents an ordinary garage door opener.

FIG. 2 represents the disposition of the electric motor and the housing of the driving mechanism which in this case is a worm and worm gear drive but could as well be a V-belt drive arrangement with pulley.

HO. 3 represents the front face of the motor and the disposition of the springs and limit switches used to stop or to reverse the polarity of the motor.

The electric motor 1, FlG.2, is connected to the housing 2 by its shaft 3 which is internally connected to the rotor of the motor at one end and to the worm 4 by a pin or screw 5 on the other end. In order to prevent wear, bushings or bearings 6 could be inserted at each end of the worm.

When the rotor of the motor starts turning in one direction the shaft 3 drives the worm 4; the worm drives the worm gear 7 which in turn drives a chain sprocket or a drum 8.

The chain sprocket, FIG.1, or the drum drives a roller chain or a cable wire 9 attached to both ends of a carriage 10 that slides on a U channel or a T bar or a tubing 11; the said carriage being attached to the door 12 by an arm 13.

When the door in its way down or up encounters an obstacle or if the door is jammed, the rotational speed of the drum, the worm gear, the worm, the shaft of the motor and its rotor reduces gradually or stops completely.

In doing so the stator or the armature of the motor being free to rotate, not being attached to any other part, will then turn in the opposite direction.

A pair of springs 14 FIG.3 attached to the base 15 of the housing 2 and to two of the tie bolts 16 of the motor, tie bolts holding end covers 17 of the motor together, will keep the armature in its normal position allowing however a rotatable movement of a few degrees in both direction.

Pending upon which direction the rotor starts turning, the armature in case of an obstruction in the travel of thedoor will turn in the opposite direction and the bolt 18 of the motor will actuate one of the limit switches 19 that will shut the motor off or reverse its polarity pending where the limit switches are connected to.

The tension in springs 16 is pre-adjusted to provide an initial resistance to the rotation movement of the armature housing. A brake may also be provided for achieving the same purpose.

This brake may consist of a threaded shaft 21, going through the base 15 of the housing 2 and, having at one end a piece of rubber or brake lining 20 that will exercise a certain pressure on the armature 17, pressure being controlled by a knob 22 at the other end of the threaded shaft.

Although a specific embodiment of the invention has just been described it will be understood that various modifications may be made thereto without departing from the invention the scope of which is only to be construed from the appended claim.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A mechanism for operating a door comprising, in combination: a reversible electric motor composed of a rotatable armature housing, of a rotor and of a rotatable shaft connected to said rotor and driven thereby; a worm fixedly received on said shaft for rotation therewith; a worm gear in working engagement with said worm; an enclosure receiving said worm and said worm gear therein; door closure actuating means operatively connected to said worm gear; a pair of limit switch means electrically connected to said motor and each disposed in spaced relationship adjacent said armature housing, said pair oflimit switch means including a first switch for stopping said motor and a second switch for causing said motor to reverse rotation of said rotor; switch actuating means mounted externally on said armature housing and disposed between said pair of switches for contacting one of said switches; a pair of spring means each having one end attached to said armature housing and the other end attached to said enclosure, said spring means preventing complete rotation of said armature housing but allowing a small rotational movement thereof when rotation of said shaft is stopped as a result of a stopping of a door closure, said rotational movement of said armature housing allowing said switch actuating means to contact said first switch to stop said motor or to contact said second switch to reverse the rotation of said rotor.

2. A mechanism as defined in claim 1 further comprising an adjustable brake composed of a threaded shaft supported on said enclosure; said threaded shaft having, at one end thereof, a lining adapted to come in contact with said armature housing and, at the other end thereof, a knob for controlling the pressure of said lining on said armature housing whereby said armature must overcome an initial friction resistance by said brake thereon before begining said small rotational movement. 

1. A mechanism for operating a door comprising, in combination: a reversible electric motor composed of a rotatable armature housing, of a rotor and of a rotatable shaft connected to said rotor and driven thereby; a worm fixedly received on said shaft for rotation therewith; a worm gear in working engagement with said worm; an enclosure receiving said worm and said worm gear therein; door closure actuating means operatively connected to said worm gear; a pair of limit switch means electrically connected to said motor and each disposed in spaced relationship adjacent said armature housing, said pair of limit switch means including a first switch for stopping said motor and a second switch for causing said motor to reverse rotation of said rotor; switch actuating means mounted externally on said armature housing and disposed between said pair of switches for contacting one of said switches; a pair of spring means each having one end attached to said armature housing and the other end attached to said enclosure, said spring means preventing complete rotation of said armature housing but allowing a small rotational movement thereof when rotation of said shaft is stopped as a result of a stopping of a door closure, said rotational movement of said armature housing allowing said switch actuating means to contact said first switch to stop said motor or to contact said second switch to reverse the rotation of said rotor.
 2. A mechanism as defined in claim 1 further comprising an adjustable brake composed of a threaded shaft supported on said enclosure; said threaded shaft having, at one end thereof, a lining adapted to come in contact with said armature housing and, at the other end thereof, a knob for controlling the pressure of said lining on said armature housing whereby said armature must overcome an initial friction resistance by said brake thereon before begining said small rotational movement. 